NEDD4L intramolecular interactions regulate its auto and substrate NaV1.5 ubiquitination

NEDD4L is a HECT-type E3 ligase that catalyzes the addition of ubiquitin to intracellular substrates such as the cardiac voltage-gated sodium channel, NaV1.5. The intramolecular interactions of NEDD4L regulate its enzymatic activity which is essential for proteostasis. For NaV1.5, this process is critical as alterations in Na+ current is involved in cardiac diseases including arrhythmias and heart failure. In this study, we perform extensive biochemical and functional analyses that implicate the C2 domain and the first WW-linker (1,2-linker) in the autoregulatory mechanism of NEDD4L. Through in vitro and electrophysiological experiments, the NEDD4L 1,2-linker was determined to be important in substrate ubiquitination of NaV1.5. We establish the preferred sites of ubiquitination of NEDD4L to be in the second WW-linker (2,3-linker). Interestingly, NEDD4L ubiquitinates the cytoplasmic linker between the first and second transmembrane domains of the channel (DI-DII) of NaV1.5. Moreover, we design a genetically encoded modulator of Nav1.5 that achieves Na+ current reduction using the NEDD4L HECT domain as cargo of a NaV1.5-binding nanobody. These investigations elucidate the mechanisms regulating the NEDD4 family and furnish a new molecular framework for understanding NaV1.5 ubiquitination.

Neuronal-epithelial cross-talk drives acinar specification via NRG1-ERBB3-mTORC2 signaling

Acinar cells are the principal secretory units of multiple exocrine organs. A single-cell, layered, lumenized acinus forms from a large cohort of epithelial progenitors that must initiate and coordinate three cellular programs of acinar specification, namely, lineage progression, secretion, and polarization. Despite this well-known outcome, the mechanism(s) that regulate these complex programs are unknown. Here, we demonstrate that neuronal-epithelial cross-talk drives acinar specification through neuregulin (NRG1)-ERBB3-mTORC2 signaling. Using single-cell and global RNA sequencing of developing murine salivary glands, we identified NRG1-ERBB3 to precisely overlap with acinar specification during gland development. Genetic deletion of Erbb3 prevented cell lineage progression and the establishment of lumenized, secretory acini. Conversely, NRG1 treatment of isolated epithelia was sufficient to recapitulate the development of secretory acini. Mechanistically, we found that NRG1-ERBB3 regulates each developmental program through an mTORC2 signaling pathway. Thus, we reveal that a neuronal-epithelial (NRG1/ERBB3/mTORC2) mechanism orchestrates the creation of functional acini.

Enzymatic analysis of WWP2 E3 ubiquitin ligase using protein microarrays identifies autophagy-related substrates

WWP2 is a HECT E3 ligase that targets protein Lys residues for ubiquitination and is comprised of an N-terminal C2 domain, four central WW domains, and a C-terminal catalytic HECT domain. The peptide segment between the middle WW domains, the 2,3-linker, is known to autoinhibit the catalytic domain, and this autoinhibition can be relieved by phosphorylation at Tyr369. Several protein substrates of WWP2 have been identified, including the tumor suppressor lipid phosphatase PTEN, but the full substrate landscape and biological functions of WWP2 remain to be elucidated. Here, we used protein microarray technology and the activated enzyme phosphomimetic mutant WWP2Y369E to identify potential WWP2 substrates. We identified 31 substrate hits for WWP2Y369E using protein microarrays, of which three were known autophagy receptors (NDP52, OPTN, and SQSTM1). These three hits were validated with in vitro and cell-based transfection assays and the Lys ubiquitination sites on these proteins were mapped by mass spectrometry. Among the mapped ubiquitin sites on these autophagy receptors, many had been previously identified in the endogenous proteins. Finally, we observed that WWP2 KO SH-SH5Y neuroblastoma cells using CRISPR-Cas9 showed a defect in mitophagy, which could be rescued by WWP2Y369E transfection. These studies suggest that WWP2-mediated ubiquitination of the autophagy receptors NDP52, OPTN, and SQSTM1 may positively contribute to the regulation of autophagy.

Multifaceted Regulation of Akt by Diverse C-Terminal Post-translational Modifications

Akt is a Ser/Thr protein kinase that regulates cell growth and metabolism and is considered a therapeutic target for cancer. Regulation of Akt by membrane recruitment and post-translational modifications (PTMs) has been extensively studied. The most well-established mechanism for cellular Akt activation involves phosphorylation on its activation loop on Thr308 by PDK1 and on its C-terminal tail on Ser473 by mTORC2. In addition, dual phosphorylation on Ser477 and Thr479 has been shown to activate Akt. Other C-terminal tail PTMs have been identified, but their functional impacts have not been well-characterized. Here, we investigate the regulatory effects of phosphorylation of Tyr474 and O-GlcNAcylation of Ser473 on Akt. We use expressed protein ligation as a tool to produce semisynthetic Akt proteins containing phosphoTyr474 and O-GlcNAcSer473 to dissect the enzymatic functions of these PTMs. We find that O-GlcNAcylation at Ser473 and phosphorylation at Tyr474 can also partially increase Akt's kinase activity toward both peptide and protein substrates. Additionally, we performed kinase assays employing human protein microarrays to investigate global substrate specificity of Akt, comparing phosphorylated versus O-GlcNAcylated Ser473 forms. We observed a high similarity in the protein substrates phosphorylated by phosphoSer473 Akt and O-GlcNAcSer473 Akt. Two Akt substrates identified using microarrays, PPM1H, a protein phosphatase, and NEDD4L, an E3 ubiquitin ligase, were validated in solution-phase assays and cell transfection experiments.

Comparative Effectiveness Analyses of Salvage Prostatectomy and Salvage Radiotherapy Outcomes Following Focal or Whole-Gland Ablative Therapy (High-Intensity Focused Ultrasound, Cryotherapy or Electroporation) for Localised Prostate Cancer

AIMS

Ablative therapy, such as focal therapy, cryotherapy or electroporation, aims to treat clinically significant prostate cancer with reduced treatment-related toxicity. Up to a third of patients may require further local salvage treatment after ablative therapy failure. Limited descriptive, but no comparative, evidence exists between different salvage treatment outcomes. The aim of this study was to compare oncological and functional outcomes after salvage robot-assisted radical prostatectomy (SRARP) and salvage radiotherapy (SRT).

MATERIALS AND METHODS

Data were collected prospectively and retrospectively on 100 consecutive SRARP cases and 100 consecutive SRT cases after ablative therapy failure in a high-volume tertiary centre.

RESULTS

High-risk patients were over-represented in the SRARP group (66.0%) compared with the SRT group (48.0%) (P = 0.013). The median (interquartile range) follow-up after SRARP was 16.5 (10.0-30.0) months and 37.0 (18.5-64.0) months after SRT. SRT appeared to confer greater biochemical recurrence-free survival at 1, 2 and 3 years compared with SRARP in high-risk patients (year 3: 86.3% versus 66.0%), but biochemical recurrence-free survival was similar for intermediate-risk patients (year 3: 90.0% versus 75.6%). There was no statistical difference in pad-free continence at 12 and 24 months between SRARP (77.2 and 84.7%) and SRT (75.0 and 74.0%) (P = 0.724, 0.114). Erectile function was more likely to be preserved in men who underwent SRT. After SRT, cumulative bowel and urinary Radiation Therapy Oncology Group toxicity grade I were 25.0 and 45.0%, grade II were 11.0 and 11.0% and grade III or IV complications were 4.0 and 5.0%, respectively.

CONCLUSION

We report the first comparative analyses of salvage prostatectomy and radiotherapy following ablative therapy. Men with high-risk disease appear to have superior oncological outcomes after SRT; however, treatment allocation does not appear to influence oncological outcomes for men with intermediate-risk disease. Treatment allocation was associated with a different spectrum of toxicity profile. Our data may inform shared decision-making when considering salvage treatment following focal or whole-gland ablative therapy.

Retrospective comparison of percutaneous balloon pericardiotomy with pericardiocentesis versus pericardiocentesis alone for management of symptomatic pericardial effusions

Background

Cardiac tamponade is a potentially life-threatening complication of pericardial effusion. Pericardiocentesis with drainage is the mainstay of treatment for patients with pericardial effusion and cardiac tamponade. Percutaneous balloon pericardiotomy (PBP) is an adjunct to pericardiocentesis that may alleviate the risk for recurrent effusion and repeat procedures. However, the efficacy of PBP plus pericardiocentesis compared to pericardiocentesis alone is not clear.

Purpose

We sought to determine whether PBP plus pericardiocentesis was associated with less recurrence of pericardial effusion than pericardiocentesis alone.

Methods

We conducted a single-centre retrospective analysis of patients ≥18 years old with non-iatrogenic pericardial effusion undergoing either pericardiocentesis alone or PBP plus pericardiocentesis for the first time. For PBP, a balloon was advanced over a guidewire until it crossed the pericardium and was then inflated until the balloon profile was fully expanded. Type of balloon used, and single or double balloon technique were left up to the operator. Recurrent pericardial effusion was defined as a large pericardial effusion on echocardiogram, pericardial effusion that caused hemodynamic compromise, or pericardial effusion that necessitated another intervention to drain at any time after initial procedure. Risk factors for recurrent pericardial effusion were also assessed.

Results

There were 208 patients who underwent pericardiocentesis, with 33 patients receiving PBP plus pericardiocentesis. In all patients, the rate of recurrent pericardial effusion was 15.9% and 15.2%, respectively (p=0.92). In patients with a cancer diagnosis at time of procedure, the rate of recurrent pericardial effusion was 17.8% and 16.7%, respectively (p=0.89). In patients with malignant pericardial effusion as confirmed by cytology, the rate of recurrent pericardial effusion was 20.4% and 13.3%, respectively (p=0.72). Patients with a connective tissue disease (CTD) had an increased odds ratio (OR) of recurrent pericardial effusion when compared to patients without a CTD (OR 3.19, 95% CI 1.31–7.77).

Conclusions

The results of this study suggest that PBP plus pericardiocentesis offers no significant benefit over pericardiocentesis alone at preventing recurrent pericardial effusion. This finding was true in all sub-groups, including patients with cancer and patients with malignant pericardial effusion. Patients with a CTD were three times more likely than patients without a CTD of having a recurrent pericardial effusion, independent of treatment strategy.

Funding Acknowledgement

Type of funding sources: None.

141 New Guidelines to Reduce Unnecessary Blood Tests, Delayed Discharge and Costs Following Robot Assisted Radical Prostatectomy

Objectives

Routine postoperative blood tests (POBT) following robot assisted radical prostatectomy (RARP) are used to evaluate the impact of surgery on pre-existing co-morbidities and to detect early complications. This practice dates back to an era of open surgery, when blood loss and complication rates were higher. We propose new guidelines to improve the specificity of POBT.

Method

The cases of 1040 consecutive patients who underwent a primary or salvage RARP at two large tertiary urology centres in the United Kingdom were retrospectively reviewed to form new guidelines. The new guidelines were prospectively validated in a sample of 300 patients.

Results

Derivation Dataset: 3% and 5% had intra- and post-operative Clavien-Dindo complications, respectively. 15% had clinical concerns postoperatively. 0.9% required perioperative transfusion. 78% had routine blood tests without clinical concerns, none of whom developed a complication. 98% of complications were suspected by clinical judgement. 6% of patients had a discharge delay of ≥ 1 day due to delayed or incomplete blood tests. Validation Dataset: No significant difference existed in complication, clinical concern or transfusion rates between the derivation and validation datasets. Number of POBT requested reduced by 73% (p < 0.001). The new guidelines improved POBT sensitivity for complications from 98% to 100% and specificity from 0% to 74%. Discharge delays reduced from 6% to 0% (p = 0.008). Cost savings were £178 per patient.

Conclusions

Postoperative complications and transfusion following RARP are rare. Routine POBT without clinical indication are unnecessary and inefficient. A guideline-based approach to POBT can reduce costs and optimise discharge without compromising patient safety or care.

283 Salvage Versus Primary Robot-Assisted Radical Prostatectomy: A Propensity-Matched Comparative Effectiveness Study from A High-Volume Tertiary Centre

Aim

Salvage Robot-Assisted Radical Prostatectomy (sRARP) is a potential treatment option for locally recurrent Prostate Cancer after non-surgical primary treatment. There are minimal data comparing outcomes between propensity-matched salvage and primary Robot-Assisted Radical Prostatectomy (RARP). We compare perioperative, oncological, and functional outcomes of sRARP with primary RARP and between sRARP post-whole and focal gland therapy.

Method

1:1 propensity-matched comparison of 146 sRARP with primary RARP from a cohort of 3,852 consecutive patients from a high-volume tertiary centre.

Results

There were no significant differences in patient characteristics between the salvage and primary RARP groups. Grade III-V Clavien-Dindo complication rates were 1.3% and 0% in the salvage and primary groups, respectively (p = 0.310). Median (IQR) follow-up was 16 (10,30) and 21 (13,33) months in the salvage and primary groups, respectively. BCR rates were 30.8% and 13.7% in the salvage and primary groups, respectively (p < 0.001). Pad-free continence rates were 79.1% and 85.4% at two years in the salvage and primary groups, respectively (p = 0.160). ED rates were 95.2% and 77.4% in the salvage and primary groups, respectively (p < 0.001). Comparing the whole gland and focal gland groups, BCR rates were 33.3% and 29.1%, respectively (p = 0.687), pad-free continence rates were 66% and 89.3%, respectively (p = 0.001), and ED rates were 98.3% and 93%, respectively (p = 0.145).

Conclusions

SRARP has similar perioperative but inferior oncological outcomes to primary RARP. Continence rates are similar to primary RARP, but potency is worse. Perioperative and oncological outcomes of sRARP after focal gland therapy are similar but continence outcomes are superior compared to sRARP after whole gland therapy.

O50 New guidelines to reduce unnecessary blood tests, delayed discharge and costs following robot assisted radical prostatectomy

Introduction

Routine postoperative blood tests (POBT) are used to evaluate the impact of surgery on pre-existing co-morbidities and to detect early complications. This practice dates back to an era of open surgery, when blood loss and complication rates were higher. We propose new guidelines to improve the specificity of POBT.

Method

The cases of 1040 consecutive patients who underwent a primary or salvage RARP at two large tertiary urology centres in the United Kingdom were retrospectively reviewed, and new guidelines were designed. The guidelines were prospectively validated in a cohort of 300 patients.

Result

Derivation Dataset 3% and 5% had intra- and post-operative Clavien-Dindo complications, respectively. 15% had clinical concerns postoperatively. 0.9% required perioperative transfusion. 78% had routine blood tests without clinical concerns, none of whom developed a complication. 98% of complications were suspected by clinical judgement. 6% of patients had a discharge delay of ≥ 1 days due to delayed or incomplete blood tests.

Validation Dataset No significant difference existed in complication, clinical concern or transfusion rates between the derivation and validation datasets. New guidelines improved sensitivity for complications from 98% to 100% and specificity from 0% to 74%. The number of blood tests requested reduced by 73% (P < 0.001). Discharge delays reduced from 6% to 0% (P = 0.008). Cost savings were £178 per patient.

Conclusion

Postoperative complications and transfusion following RARP are rare. Routine POBT without clinical indication are unnecessary and inefficient. A guideline-based approach to POBT can reduce costs and optimise discharge without compromising patient safety or care.

Take-home Message

Routine postoperative blood tests following robot assisted radical prostatectomy are often unnecessary. A guideline-based approach can reduce costs and optimise patient care.

Navigating the intricacies of cellular machinery

Voltage-gated sodium channels (Na_Vs) underlie the initiation of action potentials in various excitable cell types and are regulated by channel-interacting proteins, including the cellular calcium sensor calmodulin and fibroblast growth factor homologous factors. Both of these are known to bind the Na_V cytosolic C-terminal domain and modulate the channel’s electrophysiology, but it was unknown whether they had any allosteric interactions with each other. A recent rigorous study provides insights into the molecular interactions of these ion channels and their partners that crucially take the cellular landscape into consideration.

236 Novel Guidelines to Avoid Routine Blood Tests After Robotic Assisted Radical Prostatectomy (RARP)

Introduction

Patients undergoing RARP commonly require routine post-operative blood tests. This practice dates from an era of open surgery, with increased blood loss and complications. We aim to improve specificity of blood test requests with novel guidelines.

Method

1039 consecutive RARP patients at two tertiary urology centres in the UK were audited. Novel guidelines constructed based on risk stratified evidence from the initial audit were used to prospectively audit 133 patients.

Results

16% had clinical concerns post-operatively. 1% and 4% had an intra- and post-operative complication. Intra- or post-operative clinical judgement flagged post-operative complications in 99.9%. 80% had routine blood tests with no clinical concerns. 6% had delayed discharge due to delayed processing of blood tests. 0.9% received a peri-operative transfusion.

Re-Audit Novel guidelines reduced the number of blood tests requested from 100% to 36%. Specificity in diagnosing a complication improved from 0% to 67%. Discharge delays reduced from 6% to 0% and no post-operative complications were missed (sensitivity 100%).

Conclusions

Routine blood tests, without an indication, did not flag any additional post-operative complications. Blood transfusion is rare for RARP. Novel guidelines to request post-operative blood tests will reduce costs and discharge delays whilst maintaining appropriate patient safety and care.

Structural basis of cytoplasmic NaV1.5 and NaV1.4 regulation

Voltage-gated sodium channels (NaVs) are membrane proteins responsible for the rapid upstroke of the action potential in excitable cells. There are nine human voltage-sensitive NaV1 isoforms that, in addition to their sequence differences, differ in tissue distribution and specific function. This review focuses on isoforms NaV1.4 and NaV1.5, which are primarily expressed in skeletal and cardiac muscle cells, respectively. The determination of the structures of several eukaryotic NaVs by single-particle cryo-electron microscopy (cryo-EM) has brought new perspective to the study of the channels. Alignment of the cryo-EM structure of the transmembrane channel pore with x-ray crystallographic structures of the cytoplasmic domains illustrates the complementary nature of the techniques and highlights the intricate cellular mechanisms that modulate these channels. Here, we review structural insights into the cytoplasmic C-terminal regulation of NaV1.4 and NaV1.5 with special attention to Ca2+ sensing by calmodulin, implications for disease, and putative channel dimerization.

Functional Specialization of Human Salivary Glands and Origins of Proteins Intrinsic to Human Saliva

Salivary proteins are essential for maintaining health in the oral cavity and proximal digestive tract, and they serve as potential diagnostic markers for monitoring human health and disease. However, their precise organ origins remain unclear. Through transcriptomic analysis of major adult and fetal salivary glands and integration with the saliva proteome, the blood plasma proteome, and transcriptomes of 28+ organs, we link human saliva proteins to their source, identify salivary-gland-specific genes, and uncover fetal- and adult-specific gene repertoires. Our results also provide insights into the degree of gene retention during gland maturation and suggest that functional diversity among adult gland types is driven by specific dosage combinations of hundreds of transcriptional regulators rather than by a few gland-specific factors. Finally, we demonstrate the heterogeneity of the human acinar cell lineage. Our results pave the way for future investigations into glandular biology and pathology, as well as saliva's use as a diagnostic fluid.

Techniques and Outcomes of Salvage Robot-Assisted Radical Prostatectomy (sRARP)

BACKGROUND

Salvage Robot-Assisted Radical Prostatectomy (sRARP) has been described as feasible treatment for the management of localised prostate cancer (PCa) recurrence after primary treatment. However, no large reports have published cancer and quality outcomes.

OBJECTIVE

To report perioperative, functional and oncologic outcomes of sRARP in patients with localised PCa recurrence.

DESIGN, SETTING, AND PARTICIPANTS

We retrospectively evaluated 106 patients with local recurrence eligible for sRARP.

SURGICAL PROCEDURE

Surgery was performed using the DaVinci Si system similar to the standard approach but with adaptation to the primary treatment.

MEASUREMENTS

Peri-operative outcomes included 90-day complication rate. Functional outcomes included rates of incontinence and erectile dysfunction. Oncological outcomes included tumour staging, margin rate and recurrence.

RESULTS AND LIMITATIONS

Primary treatment was High Intensity Focused Ultrasound (HIFU) in 59 (56%) patients, 27 (25%) radiotherapy, 10 (9%) seed brachytherapy, 8 (8%) solitary androgen deprivation therapy (ADT), one (1%) cryotherapy and one (1%) electroporation / Nanoknife. Median follow-up was 2.1 years. 90-day complication rate was 8%. At two years or more, 50% were fully continent and 33% were socially continent. Continence rates tended to be better after focal compared to whole-gland treatments. Erectile dysfunction was present in 95%. Positive surgical margin rate was 39%. Biochemical recurrence occurred in 13% and local or metastatic recurrence in 11%.

CONCLUSIONS

sRARP is technically more challenging but is a feasible option in high-volume centres for treatment of recurrent PCa. Patients should be counselled that functional outcomes are inferior to primary RARP. Adjustment of surgical technique according to the primary treatment is key for good surgical outcomes.

PATIENT SUMMARY

We report our experience with sRARP for the management of localised PCa recurrence after primary treatment. This represents a feasible approach with acceptable peri-operative complications and cancer outcomes. Functional outcomes are inferior to RARP in the primary setting.

Community intervention for cardiovascular disease risk factors in Kalutara, Sri Lanka

BACKGROUND

The effectiveness of a 2015-17 community intervention to reduce cardiovascular disease (CVD) and type 2 diabetes (T2DM) risk factors is assessed in a Sri Lanka adult population, using a before-and-after study design.

METHODS

Four contiguous Public Health Midwife (PHM) areas in Kalutara district (Western Province) were exposed to a Sri Lankan designed community health promotion initiatives (without screening) to lower CVD and T2DM risk factors. Pre- and post-intervention surveys (2014, n=1,019; 2017, n=908) were of 25-64 year males (M) and females (F) from dissimilar randomly selected clusters (villages or settlements) from PHMs, with probability of selection proportional to population size, followed by household sampling, then individual selection to yield equal-probability samples. Differences in resting blood pressure (BP), fasting plasma glucose (FPG), total cholesterol, body mass index and tobacco smoking, adjusting for cluster sampling, age and socio-economic differences, were examined.

RESULTS

Hypertension prevalence declined from 25% to 16% (F) (p<.0001), and 21% to 17% (M). Both mean systolic and diastolic BP declined. T2DM declined from 18% to 13% (F), and 18% to 15% (M), as did mean fasting plasma glucose. Elevated total cholesterol declined from 21% to 15% in women (p=0.003) and mean cholesterol declined. Frequency distributions, medians and means of these continuous CVD risk factors shifted to lower levels, and were mostly statistically significant (p< 0.05).

CONCLUSIONS

Community health promotion can lower key CVD and T2DM risk factors. Lowering tobacco consumption in males and obesity remain challenges in Sri Lanka.

Koori voices: self-harm, suicide attempts, arrests and substance use among Aboriginal and Torres Strait Islander adolescents following residential treatment

BACKGROUND

Complex interacting social, economic and historical factors influence the availability and uptake of alcohol and drugs, including among Indigenous communities. Self-harm and suicide as well as homelessness and incarceration, can both precede and result from drug and alcohol use. Rates of self-harm, suicide and incarceration among Aboriginal and Torres Strait Islander people in Australia are among the highest in the world and drug and alcohol treatment programs need to address these underlying complexities. This study examines whether an 'holistic' residential drug and alcohol treatment program for adolescents, with over 30% of clients identifying as Aboriginal and Torres Strait Islander, can improve outcomes post-discharge, including reducing self-harm, suicide attempts, arrests and alcohol and drug use. The program addresses substance use, mental health, employment, accommodation, social/community and family life. Program admission and 3 months' post-discharge data from 2007 to 2016 were analysed.

RESULTS

From 2007 to 2016, 619 Aboriginal and Torres Strait Islander young people were admitted to the program; 247 stayed in the program for 30 days or more; 89 were successfully followed up three months post-discharge to determine whether there was a significant improvement from baseline using the McNemar's Test and the Wilcoxon Signed Ranks Test. On admission, 18 people (20%) of the study population reported attempting suicide in the last 3 months and 23 people (30%) reported self-harm. Most had been engaged in the criminal justice system, with 67 people (75%) having been to court and 62 people (70%) arrested one or more times in the past 3 months, with 35 people (41%) in unstable housing, reporting having lived in three or more places in the previous 6 months. At 3 months post-treatment, all (n = 18) who reported suicide attempts in the 3 months prior to admission reported no attempts in the prior 3 months at follow-up. There was also a significant reduction in self-harm with 23 young people out of the 27 who reported self-harm at baseline not reporting self-harm at follow up (85%) and in the proportion of adolescents who reported using cannabis, amphetamines and alcohol, as well as a reduction in the proportion who reported being arrested.

CONCLUSIONS

The findings provide support for an 'holistic' residential treatment program as an approach to improve health and related outcomes for Aboriginal and Torres Strait Islander young people. In addition to a focus on multiple aspects of a young person's life in treatment, culturally relevant modes of treatment and support should be a future focus to further strengthen programs when Aboriginal and Torres Strait Islander young people are over-represented in the client group.

Global knockout of ROMK potassium channel worsens cardiac ischemia-reperfusion injury but cardiomyocyte-specific knockout does not: Implications for the identity of mitoKATP

The renal-outer-medullary‑potassium (ROMK) channel, mutated in Bartter's syndrome, regulates ion exchange in kidney, but its extra-renal functions remain unknown. Additionally, ROMK was postulated to be the pore-forming subunit of the mitochondrial ATP-sensitive K+ channel (mitoKATP), a mediator of cardioprotection. Using global and cardiomyocyte-specific knockout mice (ROMK-GKO and ROMK-CKO respectively), we characterize the effects of ROMK knockout on mitochondrial ion handling, the response to pharmacological KATP channel modulators, and ischemia/reperfusion (I/R) injury. Mitochondria from ROMK-GKO hearts exhibited a lower threshold for Ca2+-triggered permeability transition pore (mPTP) opening but normal matrix volume changes during oxidative phosphorylation. Isolated perfused ROMK-GKO hearts exhibited impaired functional recovery and increased infarct size when I/R was preceded by an ischemic preconditioning (IPC) protocol. Because ROMK-GKO mice exhibited severe renal defects and cardiac remodeling, we further characterized ROMK-CKO hearts to avoid confounding systemic effects. Mitochondria from ROMK-CKO hearts had unchanged matrix volume responses during oxidative phosphorylation and still swelled upon addition of a mitoKATP opener, but exhibited a lower threshold for mPTP opening, similar to GKO mitochondria. Nevertheless, I/R induced damage was not exacerbated in ROMK-CKO hearts, either ex vivo or in vivo. Lastly, we examined the response of ROMK-CKO hearts to ex vivo I/R injury with or without IPC and found that IPC still protected these hearts, suggesting that cardiomyocyte ROMK does not participate significantly in the cardioprotective pathway elicited by IPC. Collectively, our findings from these novel strains of mice suggest that cardiomyocyte ROMK is not a central mediator of mitoKATP function, although it can affect mPTP activation threshold.

Diverse progenitor cells preserve salivary gland ductal architecture after radiation-induced damage

The ductal system of the salivary gland has long been postulated to be resistant to radiation-induced damage, a common side effect incurred by head and neck cancer patients receiving radiotherapy. Yet, whether the ducts are capable of regenerating after genotoxic injury, or whether damage to ductal cells induces lineage plasticity, as has been reported in other organ systems, remains unknown. Here, using the murine salivary gland, we show that two ductal progenitor populations, marked exclusively by KRT14 and KIT, maintain non-overlapping ductal compartments after radiation exposure but do so through distinct cellular mechanisms. KRT14⁺ progenitor cells are fast-cycling cells that proliferate in response to radiation-induced damage in a sustained manner and divide asymmetrically to produce differentiated cells of the larger granulated ducts. Conversely, KIT⁺ intercalated duct cells are long-lived progenitors for the intercalated ducts that undergo few cell divisions either during homeostasis or after gamma radiation, thus maintaining ductal architecture with slow rates of cell turnover. Together, these data illustrate the regenerative capacity of the salivary ducts and highlight the heterogeneity in the damage responses used by salivary progenitor cells to maintain tissue architecture.

Soil-transmitted helminthiasis among indigenous communities in Malaysia: Is this the endless malady with no solution?

Soil-transmitted helminths (STHs) are the most common intestinal parasitic infections of medical importance in human. The infections are widely distributed throughout the tropical and subtropical countries including Malaysia particularly among disadvantaged and underprivileged communities. This study was conducted to determine the prevalence and pattern of STH infections among Temuan indigenous subgroup. A cross sectional study was conducted among five villages in Peninsular Malaysia. Faecal samples and socioeconomic data were collected from each consented participant. Faecal samples were processed using formalin-ether sedimentation and examined under microscope. Data analysis was carried out using SPSS software programme for Windows version 24. A total of 411 participants voluntarily participated in this study. The overall prevalence of STH infections was 72.7% (95% CI = 68.2 - 77%). The most common STH species recorded was Trichuris trichiura (58.4%, 95% CI = 53.5 - 63.2%) followed by Ascaris lumbricoides (45.5%, 95% CI = 40.6 - 50.5%) and hookworm (23.1%, 95% CI = 19.1 - 27.5%). Multivariate analysis demonstrated that using untreated water was a significant predictor of STH infections in these communities. Our findings demonstrated that STH infections are still prevalent and co-exist with the low SES among this subgroup. Poverty and poor sanitation are the leading factors contributing to this malady. Hence, the reassessments of the existing control measures are needed.

Salivary glands regenerate after radiation injury through SOX2-mediated secretory cell replacement

Salivary gland acinar cells are routinely destroyed during radiation treatment for head and neck cancer that results in a lifetime of hyposalivation and co-morbidities. A potential regenerative strategy for replacing injured tissue is the reactivation of endogenous stem cells by targeted therapeutics. However, the identity of these cells, whether they are capable of regenerating the tissue, and the mechanisms by which they are regulated are unknown. Using in vivo and ex vivo models, in combination with genetic lineage tracing and human tissue, we discover a SOX2+ stem cell population essential to acinar cell maintenance that is capable of replenishing acini after radiation. Furthermore, we show that acinar cell replacement is nerve dependent and that addition of a muscarinic mimetic is sufficient to drive regeneration. Moreover, we show that SOX2 is diminished in irradiated human salivary gland, along with parasympathetic nerves, suggesting that tissue degeneration is due to loss of progenitors and their regulators. Thus, we establish a new paradigm that salivary glands can regenerate after genotoxic shock and do so through a SOX2 nerve-dependent mechanism.

Aire-deficient mice provide a model of corneal and lacrimal gland neuropathy in Sjögren's syndrome

Sjögren's syndrome (SS) is a chronic, autoimmune exocrinopathy that leads to severe dryness of the mouth and eyes. Exocrine function is highly regulated by neuronal mechanisms but little is known about the link between chronic inflammation, innervation and altered exocrine function in the diseased eyes and exocrine glands of SS patients. To gain a better understanding of neuronal regulation in the immunopathogenesis of autoimmune exocrinopathy, we profiled a mouse model of spontaneous, autoimmune exocrinopathy that possess key characteristics of peripheral neuropathy experienced by SS patients. Mice deficient in the autoimmune regulator (Aire) gene developed spontaneous, CD4+ T cell-mediated exocrinopathy and aqueous-deficient dry eye that were associated with loss of nerves innervating the cornea and lacrimal gland. Changes in innervation and tear secretion were accompanied by increased proliferation of corneal epithelial basal cells, limbal expansion of KRT19-positive progenitor cells, increased vascularization of the peripheral cornea and reduced nerve function in the lacrimal gland. In addition, we found extensive loss of MIST1+ secretory acinar cells in the Aire -/- lacrimal gland suggesting that acinar cells are a primary target of the disease, Finally, topical application of ophthalmic steroid effectively restored corneal innervation in Aire -/- mice thereby functionally linking nerve loss with local inflammation in the aqueous-deficient dry eye. These data provide important insight regarding the relationship between chronic inflammation and neuropathic changes in autoimmune-mediated dry eye. Peripheral neuropathies characteristic of SS appear to be tightly linked with the underlying immunopathological mechanism and Aire -/- mice provide an excellent tool to explore the interplay between SS-associated immunopathology and peripheral neuropathy.